Electrical connectors are used in many electronic systems. It is generally easier and more cost effective to manufacture a system on several printed circuit boards or substrates which are joined together with electrical connectors than it is to manufacture a single, very complex circuit board to provide the desired system functionality.
Where two circuits, each positioned on a different printed circuit board or substrate, are intended to be connected using surface pads, various structures in the form of pressure connection members have been used. These interconnect members are often molded into an elastomer or rigid cavity pad. The elastomer or rigid cavity pad provides support and alignment, a means for attachment to the substrate, and protection from the environment before the connection is made.
These pressure mounted interconnect members and support structures are sandwiched between parallel substrate surfaces and force is applied, roughly perpendicular to the substrates, to make the connection between the electrical circuits. The perpendicular force direction is generally desirable for easy assembly of one substrate to another.
The interconnect members typically contact a pad on the surface of the substrate. The signals pass from these surface pads through vias to inner layer trace constructions. Interconnect structures using the central portion of a pad to facilitate contact, typically require the surface pads to be attached to via pads to make the connection to an inner layer. Thus, two pads are required to make the connection.
One drawback of the above described approach is that using a supporting structure to organize interconnect members and secure them to the substrate generally adds additional cost and manufacturing complexity to the interconnect system. This complexity is passed on to all different sized configurations of the supporting structure. That is, each different configuration would typically require a unique supporting structure design adding further complexity to supporting a family of interconnect systems.
An additional drawback is that oxides and other debris often accumulate on the contact surfaces of these interconnection structures. This oxidation and debris can often prove an obstacle to establishing a reliable connection.
A further drawback is the requirement of two pads on the substrate to make a single connection. This dual pad approach uses excessive surface area in an area where real estate is generally at a premium. Moreover, the additional pad can also be a source of additional capacitance and negatively affect the signal quality as it passes through that portion of the circuit.
In accordance with one embodiment of the present invention, a conductive member for providing an electrical connection between two conductive surfaces is provided. The conductive member includes a spring action contact surface at a first end and a compliant interference fit contact surface at a second end. With such an arrangement a need for a supporting structure for the conductive members is eliminated thus providing a less complicated connector solution which is easily manufactured at a lower cost.
In accordance with a second embodiment of the present invention, a dielectric material is used to electrically isolate a first half of the connector from a second half of the connector. With such an arrangement, a differential signal may be transferred through the connector.
In accordance with a third embodiment of the connector, the compliant interference fit contact is supported within a conductive hole in a printed circuit board and the spring action surface contact provides an electrical connection to a conductive element disposed on a second surface. With such an arrangement, a mechanical wiping action against the conductive element is provided which facilitates breaking through oxides that develop on the conductive element and further for clearing minute debris from the actual mated zone that passes the electrical signal from the pad on the substrate to a portion of the interconnection structure, thus providing a more reliable connection.
In accordance with a fourth embodiment of the present invention, an interconnection system between a printed circuit board and a second surface is provided. The interconnection system includes an arrangement of conductive elements disposed on said second surface and an arrangement of first electrical connectors. Each of the electrical connectors includes a compliant interference fit contact disposed at a first end of the connector, the compliant interference fit contact being supported within a conductive hole in the printed circuit board. Each electrical connector further includes a spring action surface contact disposed at a second end of the connector, the spring action surface contact providing an electrical connection to one of the conductive elements. With such an arrangement, only a single surface pad is required by the interconnect solution, thus minimizing the capacitance of the connection. In addition, a flexible interconnection system is provided in which signals may be passed from one circuit substrate to another circuit substrate at multiple locations on each substrate rather than in a traditional grouping of signal interconnects at a single area of the substrate.